Is Molly Weasley a fearsome or a sabre-tooth tiger?

Five days. Cinque jours. Wow. Time is both flying and crawling along.

I'm now reading Harry Potter and the Chamber of Secrets, in French. It's a lot of fun. In this book, we make our first visit to the Burrow, the home of the Weasleys, which in French translates to "Le Terrier". My research suggests that this is a fairly straightforward translation of the the phrase "The Burrow" but it sounds weird to me since, in English, a terrier is a dog.

At the start of this book, when Fred, George and Ron return to the Burrow in the flying care after rescuing Harry from the Dursley's, Mrs. Weasley storms out to meet them, furious. J.K. describes her for the first time in a manner that suggests the powerhouse she turns out to be in Book Seven: in French, the description is "une tigresse redoutable", which means something like "a fearsome tiger". In the English, J.K. describes Molly as "a sabre-tooth tiger".

I wonder why the change, the re-interpretation in translation. Perhaps French people wouldn't think of a sabre-tooth tiger as being particularly frightening.